--- title: "EPUB Book Export" description: "Fumadocs provides EPUB book export capabilities via the fumadocs-epub package, allowing documentation collections to be packaged into portable e-reader books. By integrating with epub-gen-memory, t..." last_updated: "2026-10-12T07:53:59.736226+00:00" canonical_url: "https://www.doc0.dev/docs/e8872a72-1909-479c-b585-dc74c6e26726/technical/developer-tooling/epub-book-export" ---
Relevant source files The following files were used as context for generating this wiki page: - [packages/epub/src/index.ts](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/epub/src/index.ts) - [packages/cli/src/commands/export-epub.ts](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/cli/src/commands/export-epub.ts) - [packages/epub/package.json](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/epub/package.json) - [packages/epub/src/toc-builder.ts](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/epub/src/toc-builder.ts) - [packages/asyncapi/src/generate-file.ts](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/asyncapi/src/generate-file.ts) - [packages/epub/src/types.ts](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/epub/src/types.ts) - [packages/mdx/src/runtime/dynamic.ts](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/mdx/src/runtime/dynamic.ts) - [packages/cli/src/index.ts](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/cli/src/index.ts) - [packages/openapi/src/utils/pages/builder.ts](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/openapi/src/utils/pages/builder.ts) - [packages/content/src/index.ts](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/content/src/index.ts) - [packages/preview/src/pages/...slugs.tsx](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/preview/src/pages/%5B...slugs%5D.tsx) - [packages/content/src/runtime.ts](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/content/src/runtime.ts) - [packages/asyncapi/src/utils/pages/builder.ts](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/asyncapi/src/utils/pages/builder.ts) - [packages/obsidian/src/index.ts](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/obsidian/src/index.ts) - [packages/asyncapi/src/server/index.tsx](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/asyncapi/src/server/index.tsx) - [packages/python/src/convert.ts](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/python/src/convert.ts) - [packages/openapi/src/generate-file.ts](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/openapi/src/generate-file.ts) - [packages/create-app/src/bin.ts](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/create-app/src/bin.ts) - [packages/core/src/source/page-tree/builder.ts](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/core/src/source/page-tree/builder.ts) - [packages/preview/src/lib/source/storage.ts](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/preview/src/lib/source/storage.ts) - [packages/epub/tsdown.config.ts](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/epub/tsdown.config.ts) - [packages/mdx/src/plugins/index-file.ts](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/mdx/src/plugins/index-file.ts) - [packages/core/src/mdx-plugins/rehype-toc.ts](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/core/src/mdx-plugins/rehype-toc.ts) - [packages/core/package.json](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/core/package.json) - [packages/core/src/source/loader.ts](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/core/src/source/loader.ts) - [packages/asyncapi/src/utils/pages/preset-auto.ts](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/asyncapi/src/utils/pages/preset-auto.ts) - [packages/asyncapi/src/utils/pages/to-text.ts](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/asyncapi/src/utils/pages/to-text.ts) - [packages/mdx/src/runtime/server.ts](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/mdx/src/runtime/server.ts) - [packages/api-docs/tsdown.config.ts](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/api-docs/tsdown.config.ts) - [packages/asyncapi/src/utils/pages/to-static-data.ts](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/asyncapi/src/utils/pages/to-static-data.ts)
## Overview Fumadocs provides EPUB book export capabilities via the `fumadocs-epub` package, allowing documentation collections to be packaged into portable e-reader books. By integrating with `epub-gen-memory`, the export pipeline processes documentation sources, flattens navigation page trees, resolves relative assets and cover images, and compiles markdown content into formatted EPUB buffers. Sources: [packages/epub/src/index.ts:1-150](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/epub/src/index.ts#L1-L150), [packages/epub/package.json:1-62](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/epub/package.json#L1-L62) ## Epub generation entrypoint ### Programmatic export pipeline The core export functionality is exposed through the `exportEpub` function in `packages/epub/src/index.ts`. This asynchronous function accepts an export configuration object, collects and filters documentation pages from the [source loader](https://www.doc0.dev/docs/e8872a72-1909-479c-b585-dc74c6e26726/technical/core-architecture/source-loader), converts raw markdown content into HTML, and packages the chapters into an EPUB buffer using `epub-gen-memory`. ```typescript export async function exportEpub( options: EpubExportOptions, ): Promise ``` Sources: [packages/epub/src/index.ts:64-66](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/epub/src/index.ts#L64-L66) The pipeline executes the following sequence of transformations to produce the final book: ```mermaid sequenceDiagram participant Source as Source Loader participant Export as exportEpub participant Markdown as markdownToHtml participant EpubGen as epub-gen-memory Source->>Export: getPageTree() / getPages() Export->>Export: Apply include/exclude filters loop For each filtered page Export->>Markdown: Get raw text & convert to HTML Markdown-->>Export: HTML chapter content end Export->>EpubGen: epub(epubOptions, chapters) EpubGen-->>Export: EPUB Buffer Export->>Export: Write to outputPath (if defined) ``` Sources: [packages/epub/src/index.ts:93-149](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/epub/src/index.ts#L93-L149) > [!NOTE] > If the `outputPath` option is specified in `EpubExportOptions`, the resulting buffer is automatically written to disk using `node:fs/promises` with recursive directory creation enabled. Otherwise, the raw `Buffer` is simply returned to the caller. Sources: [packages/epub/src/index.ts:144-149](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/epub/src/index.ts#L144-L149) ### Default export configuration and fallbacks The `exportEpub` function establishes defaults for missing metadata properties, styles, and paths. The configuration object passed to `epub-gen-memory` configures chapter numbering, [table of contents](https://www.doc0.dev/docs/e8872a72-1909-479c-b585-dc74c6e26726/technical/ui-layouts/table-of-contents) titles, and asset resolvers. | Parameter | Default Value / Fallback | Description | | :--- | :--- | :--- | | `author` | `'anonymous'` | Author string or array of authors; normalized to an array before passing to `epub-gen-memory`. | | `language` | `'en'` | Two-letter language code assigned to the `lang` option. | | `publisher` | `'anonymous'` | Publisher metadata string. | | `css` | `defaultEpubStyles` | Custom stylesheet string or default EPUB styles. | | `publicDir` | `path.resolve('public')` | Public directory path for resolving absolute asset references. | | `prependChapterTitles` | `true` | Hardcoded boolean flag passed to `epubOptions`. | | `numberChaptersInTOC` | `true` | Hardcoded boolean flag passed to `epubOptions`. | | `tocTitle` | `'Table of Contents'` | Hardcoded TOC heading string passed to `epubOptions`. | Sources: [packages/epub/src/index.ts:80-90](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/epub/src/index.ts#L80-L90), [packages/epub/src/index.ts:124-135](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/epub/src/index.ts#L124-L135) > [!WARNING] > When `getMarkdown` is not explicitly provided in the options, the function attempts to invoke `page.data.getText('raw')`. If this call fails or the method is missing, a warning is logged to the console, and the page is skipped during chapter generation. Sources: [packages/epub/src/index.ts:70-78](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/epub/src/index.ts#L70-L78) ## Export configuration and schema ### Type definitions and configuration options The configuration schema for EPUB generation is defined through TypeScript interfaces in `packages/epub/src/types.ts`. The base `EpubConfig` interface accepts generic loader configurations to provide type safety across source collections, defining metadata properties, filtering predicates, and path resolutions. ```typescript export interface EpubConfig { /** Book title */ title: string; /** Author name(s) */ author?: string | string[]; /** Book description */ description?: string; /** Language code (e.g. 'en') */ language?: string; /** Publisher name */ publisher?: string; /** Cover image - URL, file path, or path relative to public dir */ cover?: string; /** Output file path - if set, writes to file in addition to returning buffer */ outputPath?: string; /** Filter: include only these pages. Applied first (only pages where includePages(page) === true are considered). */ includePages?: (page: Config['page']) => boolean; /** Filter: exclude these pages. Applied after includePages (removes pages from the include-filtered set). */ excludePages?: (page: Config['page']) => boolean; /** Custom CSS for the EPUB */ css?: string; /** Public directory for resolving /public/... image paths */ publicDir?: string; } ``` Sources: [packages/epub/src/types.ts:3-26](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/epub/src/types.ts#L3-L26) The extension interface `EpubExportOptions` combines `EpubConfig` with required source loader outputs and custom markdown retrieval hooks. ```typescript export interface EpubExportOptions< Config extends LoaderConfig = LoaderConfig, > extends EpubConfig { /** Fumadocs source (from loader()) */ source: LoaderOutput; /** function to get page Markdown content */ getMarkdown?: (page: Config['page']) => string | undefined | Promise; } ``` Sources: [packages/epub/src/types.ts:28-35](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/epub/src/types.ts#L28-L35) | Property Name | Type | Description | | :--- | :--- | :--- | | `title` | `string` | Book title for the generated EPUB archive. | | `author` | `string \| string[]` | Author name or list of author names. | | `description` | `string` | Book description metadata. | | `language` | `string` | Language code for the document (e.g., `'en'`). | | `publisher` | `string` | Publisher metadata string. | | `cover` | `string` | Cover image reference (URL, absolute file path, or public-relative path). | | `outputPath` | `string` | Optional file system destination path to write the EPUB buffer. | | `includePages` | `(page: Config['page']) => boolean` | Initial inclusion filter predicate applied to pages. | | `excludePages` | `(page: Config['page']) => boolean` | Exclusion filter predicate applied after `includePages`. | | `css` | `string` | Custom CSS stylesheet string for the EPUB package. | | `publicDir` | `string` | Root public directory path used for resolving absolute asset paths. | | `source` | `LoaderOutput` | Fumadocs documentation source object generated via `loader()`. | | `getMarkdown` | `(page: Config['page']) => string \| undefined \| Promise` | Custom asynchronous or synchronous function to retrieve raw page Markdown content. | Sources: [packages/epub/src/types.ts:3-35](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/epub/src/types.ts#L3-L35) > [!NOTE] > Page filtering executes in a strict two-stage sequence: `includePages` runs first to restrict the working set, followed immediately by `excludePages` which removes matching entries from the remaining subset. Sources: [packages/epub/src/index.ts:102-106](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/epub/src/index.ts#L102-L106) ### Source loader integration interfaces The integration layer bridges Fumadocs core source loader outputs with export options by consuming types from `fumadocs-core/source`. When `exportEpub` executes, it extracts documentation through `source.getPageTree()` or falls back to `source.getPages()` if tree traversal yields no elements. ```typescript // Get pages in tree order (navigation order) const pageTree = source.getPageTree(); const orderedPages = getPagesInTreeOrder(pageTree, (node) => source.getNodePage?.(node)).filter( (p): p is Page => p != null, ); // Fallback to getPages() if tree order yields no pages (e.g. i18n) const pages = orderedPages.length > 0 ? orderedPages : source.getPages(); ``` Sources: [packages/epub/src/index.ts:92-100](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/epub/src/index.ts#L92-L100) > [!CAUTION] > If a page lacks a title property in its data object, the exporter falls back to utilizing the final segment of the page's URL slugs array, defaulting to `'Untitled'` if both values are missing. Sources: [packages/epub/src/index.ts:116-116](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/epub/src/index.ts#L116-L116) ## Page tree flattening ### Navigation tree traversal The page tree traversal relies on `getPagesInTreeOrder` from `packages/epub/src/toc-builder.ts` to transform a Fumadocs navigation structure into a sequential array of pages. It executes a depth-first traversal of both main children and fallback children using `flattenTree` from `fumadocs-core/page-tree`. ```typescript export function getPagesInTreeOrder( pageTree: PageTree.Root, getNodePage: (node: PageTree.Item) => Page | undefined, ): Page[] { const mainItems = flattenTree(pageTree.children); const fallbackItems = pageTree.fallback ? flattenTree(pageTree.fallback.children) : []; const items = [...mainItems, ...fallbackItems]; const pages: Page[] = []; for (const item of items) { const page = getNodePage(item); if (page) { pages.push(page); } } return pages; } ``` Sources: [packages/epub/src/toc-builder.ts:8-25](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/epub/src/toc-builder.ts#L8-L25) > [!NOTE] > If tree-order traversal returns an empty array due to internationalization structures or custom configurations, `exportEpub` falls back to using `source.getPages()` directly to populate the chapter collection. Sources: [packages/epub/src/index.ts:98-100](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/epub/src/index.ts#L98-L100) ### Chapter filtering and title resolution Once ordered pages are collected, they undergo filtering via optional `includePages` and `excludePages` predicate functions before being converted into EPUB chapters. Each valid page retrieves its raw markdown content and maps its title through a fallback chain from `page.data.title` to the final slug segment. ```typescript const filteredPages = pages.filter((page) => { if (includePages && !includePages(page)) return false; if (excludePages && excludePages(page)) return false; return true; }); const chapters: { title: string; content: string }[] = []; for (const page of filteredPages) { const markdown = await getMarkdown(page); if (!markdown) continue; const pageDir = getPageDir(page, cwd); const html = await markdownToHtml(markdown, pageDir, publicDir); const pageTitle = page.data.title ?? page.slugs[page.slugs.length - 1] ?? 'Untitled'; chapters.push({ title: pageTitle, content: html, }); } ``` Sources: [packages/epub/src/index.ts:102-122](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/epub/src/index.ts#L102-L122) ## Asset and cover resolution ### Path resolution functions The exporter handles file system locations and resource URLs using dedicated helper utilities defined in `packages/epub/src/index.ts`. The `getPageDir` function determines the base directory for a given page by inspecting its `absolutePath` or falling back to resolving its relative path against the current working directory (`cwd`). ```typescript function getPageDir(page: Page, cwd: string): string { if (page.absolutePath) { return path.dirname(page.absolutePath); } return path.resolve(cwd, path.dirname(page.path)); } ``` Sources: [packages/epub/src/index.ts:16-21](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/epub/src/index.ts#L16-L21) Cover image references are normalized through `resolveCoverPath`, which supports absolute URLs, file schemes, public directory paths, and relative file paths. If a cover path begins with a slash, it resolves against the designated `publicDir` or falls back to a default `public` folder inside `cwd`. ```typescript function resolveCoverPath( cover: string | undefined, cwd: string, publicDir?: string, ): string | undefined { if (!cover) return undefined; if (cover.startsWith('file://') || cover.startsWith('http://') || cover.startsWith('https://')) return cover; if (cover.startsWith('/')) { const base = publicDir ?? path.join(cwd, 'public'); return pathToFileUrl(path.join(base, cover.slice(1))); } return pathToFileUrl(path.resolve(cwd, cover)); } ``` Sources: [packages/epub/src/index.ts:26-39](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/epub/src/index.ts#L26-L39) > [!NOTE] > File paths converted to URLs utilize `pathToFileURL` from Node's standard library to ensure cross-platform compatibility when passed to the EPUB generation memory backend. Sources: [packages/epub/src/index.ts:41-43](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/epub/src/index.ts#L41-L43) ### Cover path resolution schemes | Input Prefix or Format | Resolution Behavior | Example Output / Destination | | :--- | :--- | :--- | | `file://` | Returned unmodified as a direct file URL. | `file:///path/to/cover.png` | | `http://` / `https://` | Returned unmodified as a remote network URL. | `https://example.com/cover.png` | | `/` (Absolute public path) | Joined with `publicDir` (or `cwd/public`), stripped of the leading slash, and converted via `pathToFileURL`. | `file:///path/to/project/public/cover.png` | | Relative path | Resolved directly against `cwd` and converted via `pathToFileURL`. | `file:///path/to/project/assets/cover.png` | Sources: [packages/epub/src/index.ts:31-39](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/epub/src/index.ts#L31-L39) ## CLI scaffolding command ### Command-line integration and options The [Fumadocs CLI](https://www.doc0.dev/docs/e8872a72-1909-479c-b585-dc74c6e26726/technical/developer-tooling/fumadocs-cli) exposes the EPUB export utility under the `export epub` command via commander in `packages/cli/src/index.ts`. It accepts a required framework option along with output path and scaffolding configuration flags. ```typescript const exportCmd = program.command('export').description('export documentation to various formats'); exportCmd .command('epub') .description('export documentation to EPUB format (run after production build)') .requiredOption('--framework ', 'React framework: next, tanstack-start, react-router, waku') .option('--output ', 'output file path', 'docs.epub') .option('--scaffold-only', 'only scaffold the EPUB route, do not copy') .action(async (options: { output?: string; framework: string; scaffoldOnly?: boolean }) => { await exportEpub({ output: options.output, framework: options.framework, scaffoldOnly: options.scaffoldOnly, }); }); ``` Sources: [packages/cli/src/index.ts:55-69](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/cli/src/index.ts#L55-L69) The command relies on framework identifiers defined during export execution. The supported framework values and their corresponding behavior are managed through validation routines in `export-epub.ts`. | Framework Option | Validation and Build Pathing Behavior | | :--- | :--- | | `next` | Validates Next.js configuration files (`next.config.js`, `next.config.ts`, `next.config.mjs`) or package dependencies (`next`) alongside `app` or `pages` directory presence. Scaffolds `/export/epub/route.ts` automatically. | | `tanstack-start` | Validates against framework path rules; requires manual prerender route configuration targeting standard build paths. | | `react-router` | Validates against framework path rules; requires manual prerender route configuration targeting standard build paths. | | `waku` | Validates against framework path rules; requires manual prerender route configuration targeting standard build paths. | Sources: [packages/cli/src/commands/export-epub.ts:109-140](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/cli/src/commands/export-epub.ts#L109-L140), [packages/cli/src/index.ts:60-60](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/cli/src/index.ts#L60-L60) ### Route scaffolding and project detection When executing `exportEpub` with the Next.js framework, the CLI inspects the working directory via `findAppDir` to locate either the `app/` or `src/app/` directory. If an existing route is absent at `app/export/epub/route.ts`, it provisions the endpoint using standard templates. ```typescript async function scaffoldEpubRoute(cwd: string): Promise { const appDir = await findAppDir(cwd); if (!appDir) { console.error(picocolors.red('Could not find app directory (app/ or src/app/)')); return false; } const routePath = path.join(appDir, 'export', 'epub', 'route.ts'); if (await exists(routePath)) { console.log(picocolors.yellow('EPUB route already exists at'), routePath); return true; } await fs.mkdir(path.dirname(routePath), { recursive: true }); await fs.writeFile(routePath, API_ROUTE_TEMPLATE); console.log(picocolors.green('Created EPUB route at'), routePath); return true; } ``` Sources: [packages/cli/src/commands/export-epub.ts:79-96](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/cli/src/commands/export-epub.ts#L79-L96) > [!WARNING] > If a Next.js [project structure](https://www.doc0.dev/docs/e8872a72-1909-479c-b585-dc74c6e26726/technical/getting-started/project-structure) cannot be verified via config files or dependency maps when `--framework next` is specified, the CLI terminates immediately with code `1` and outputs a project root error message. Sources: [packages/cli/src/commands/export-epub.ts:133-140](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/cli/src/commands/export-epub.ts#L133-L140) If the `fumadocs-epub` package is missing from project dependencies, the CLI attempts automatic installation using `pnpm`, `bun`, or `npm` depending on execution context. For Next.js deployments, the environment variable `EXPORT_SECRET` must be configured to authenticate requests against the running production server. ```typescript // Check for fumadocs-epub dependency if (!pkg) { console.error( picocolors.red('Cannot read or parse package.json. Ensure it exists and is valid JSON.'), ); process.exit(1); } const deps = { ...pkg.dependencies, ...pkg.devDependencies }; if (!deps['fumadocs-epub']) { console.log(picocolors.yellow('\nInstalling fumadocs-epub...')); const packageManager = process.env.npm_execpath?.includes('pnpm') ? 'pnpm' : process.env.npm_execpath?.includes('bun') ? 'bun' : 'npm'; const installCmd = `${packageManager} add fumadocs-epub`; try { await execAsync(installCmd, { cwd }); } catch (err: unknown) { const stderr = err && typeof err === 'object' && 'stderr' in err ? String((err as { stderr?: string }).stderr) : ''; console.error(picocolors.red(`Failed to install fumadocs-epub. Command: ${installCmd}`)); if (stderr) console.error(stderr); process.exit(1); } } if (framework === 'next') { const secret = process.env.EXPORT_SECRET; if (!secret) { console.error( picocolors.red('EXPORT_SECRET is required for Next.js export. Set it in your environment.'), ); process.exit(1); } ``` Sources: [packages/cli/src/commands/export-epub.ts:172-208](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/cli/src/commands/export-epub.ts#L172-L208) > [!CAUTION] > Network fetching of the EPUB binary from the Next.js endpoint enforces a strict 30-second timeout via `AbortController`, aborting the request and exiting with an error if the server fails to respond. Sources: [packages/cli/src/commands/export-epub.ts:211-218](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/cli/src/commands/export-epub.ts#L211-L218), [packages/cli/src/commands/export-epub.ts:237-240](https://github.com/blade47/fumadocs/blob/a9f988897e7dc4ef3d62b2865d80da2f5607701e/packages/cli/src/commands/export-epub.ts#L237-L240) ## Related - [Fumadocs CLI](https://www.doc0.dev/docs/e8872a72-1909-479c-b585-dc74c6e26726/technical/developer-tooling/fumadocs-cli) ## Sitemap See the full [sitemap](https://www.doc0.dev/docs/e8872a72-1909-479c-b585-dc74c6e26726/llms.txt) for all pages in this wiki.